Blasting detonator



Patented Dec. l2, i922.

v v en,

WILHELM ESGHBAGE, OF TROISDORF; GEEMATW.

BLASTING DEL'OlTATDR.

Lilo Drawing.

"with a top charge of tulminate of mercury,

shells have hitherto been used which are made of copper. brass zinc orsimilar metals. Shells of this kind, particularly nine and brass shells.have however the .lisadvantage that: when they are clipped on to thequickmatch by means of the clamping" tongs the are easily split with theresult that firstly they are liable to explode prematurely and secondlyitis impossible to make a tight joint with the quick-match. For thisreason misiires very easilv occur in bore holes which contain water.Even the copper shells possess this uisadvantage, although in a lesserdegree, as the metal due to its being repeatedly worked is too brittle.

The use of aluminium in place of copper or brass for the manufacture ofblastingdetonators shells has hitherto not been suggested as this metalis completely destroyed in a short time by the tulminate of mercury.

It has now been Found possible to manufacture a blasting detonator, theshell of which consists of aluminium and the charge thereof of leadazide. lead azide mixtures or similar materials, which behave'inertlytowards this metal and which is free from the above mentioneddisadvantages, Splitting of the metal when clamping the shell on to thequick-match is precluded. on account of the malleability or" thealuminium. wnereby pren'iature explosion is avoided and a tight jointsecured w ith the quick-match thus preventing the. penetration of anywater which there may be in the bore hole into the percussion caps.

its it not necessary to use an inner cap for these new blastingdetonators. the advantage of greater surface of ignition 1s secured insalt. ion to the saving in metal.

With regard to storage in damp places, experiments whiclrhave beencarried out for several years have proved that aluminium caps loaded,for example, in their-lower part with tetranitromethylaniline and withApplication filed February 3, 1921.

Serial No. 442,279

a top charge of lead azide or mixtures of lead azide or the likecletonating composition which are inert towards this metal showed nooxidation phenomena whatsoever. Even caps stored in the outlet currentof a Vestphalian mine for a longtime had neither be come decomposed noroxidized and bore no signs of this kind. lVhen fired at a leaden plate anormal image was also obtained. This fact, that isto say thedisinclination of aluminium to oxidize of itself, is therefore of greatimportance for the manufacture of blastingdetonators.

The easy malleability of aluminium is 010- viated by the drawing processwhich the shell has to go through from the strip up to its completion.The shell thus acquires a sutiicient degree of hardness which protectsit from distortion. By this means also any loosening or crumbling ot'the loading is prevented especially ii the loading contains an admixtureof some adhesive substance and is forced in] under high pressure. Thedead pressing of the lohding which very easily occurs with {ulminate ofmercury is in this case impossible.

The technical advance of the present invention is therefore to be foundin the fact that in place of copper. brass or zinc aluminium can he usedfor the manufacture of shells for blasting detonators. Furthermore thesealuminium caps have in comparison with copper caps with exactly the samecharge a much greater co-etlicient oi initiation. Experiments with theTrauzl leaden block as well as transmission firings have shown thesecaps to be free from objection.

A further proof of the superiority of these caps compared with copperonesis that the aluminium caps when fired at the lea'den plate show aconsiderably liner radiation.

Having now particularly described and ascertained the nature of my saidinvention and inwhat manner the same' is to be per formed, I declarethat what I claim is in the manutacture of blasting detonators the useof an aluminium shell with a loadin of lead azide or n'iixtures of leadazide an similar detonet 11g: c ositions which are inert towards saidand which can be easily clipped quick-match by the s clamping tongs.

Signed st 'lroisdort n the State of Ger many this l5' dlly 6i DBC8mb8l1920 was esonnao'n;

